Electrical switching contacts and switching devices known in the prior art perform switching functions in electrical switching devices such as relays or other electrical switching elements. The switching devices have drive systems that move at least one switching contact via actuators, in order to bring a counter contact into electrically conductive contact or remove it therefrom. The actuators thus move one or more switching contacts in one switching direction towards the counter contacts or, in a counter switching device, away from them, and maintain a circuit formed by the contacts and counter contacts arranged at the switching contacts in a closed or open state.
In switching devices such as protectors or relays, contact forces acting in the switching direction are applied by drive systems driving the actuator that brings the contacts into contact with the counter contacts. In order to ensure secure, uninterrupted contact between the switching contacts and the counter contacts, in particular in the event of vibrations or pulses, the drive system and the actuator may be designed to move the switching contact with overtravel in the direction of the counter contact. A contact on the switching contact thus comes into contact with the counter contact before the actuator has reached its final position; a switching path followed by the switching element on the switching contact to transfer it from an open position of the switching contact into the closed position is shorter than an actuation path followed by the actuator acting on the switching contact in the same transition. In the closed state, the actuation section is thus subject to a force with which the contact of the switching contact is kept in contact with the counter contact.
To release the switching contact from the counter contact during the transition of the switching device from the closed to the open position, a resetting force must be generated counter to the switching direction. This resetting force may be generated by the actuator, as well as by a spring section of the switching contact.
Particularly in switching devices used for high currents, however, problems may arise during the transition from the closed into the open state if the switching contact or its contact element is welded to the counter contact. This may occur when short circuit currents arise from malfunctions of an apparatus containing the switching device. In some instances, the counter switching forces are not sufficient to release the switching contact from the counter contact.